The invention relates to an optical multiplexer comprising at least one graded-index rod lens, which carries input light-wave conductors which merge onto an end face and whose radiations are passed into an area at which the radiations are received by an output light-wave conductor. Such multiplexers are used in optical data communication systems.
In a star coupler known from U.S. Pat. No. 3,937,557, in an inverse mode of operation several light-wave conductors (LWC's) are coupled each through a graded-index rod lens (GRIN-rod lens) to several LWC's of a common GRIN-rod lens. Such a star coupler cannot be used as a multiplexer without further expedients.